diff --git a/Makefile b/Makefile
index 9e7f50b..e5ebd45 100755
--- a/Makefile
+++ b/Makefile
@@ -18,7 +18,8 @@ dflags = -MT $@ -MMD -MP -MF $(@:%.o=%.d)
 #  $TARGETS is provided by Makefile.cfg.
 #
 
-TARGETS := $(filter-out fxconv fxsdk,$(TARGETS))
+TARGETS := $(filter-out fxconv,$(TARGETS))
+TARGETS := $(TARGETS:fxsdk=fxsdk.sh)
 bin = $(TARGETS:%=bin/%)
 
 # fxconv has no sources files because it's written in Python, and fxsdk has no
@@ -33,15 +34,26 @@ lex = $($1:%.l=build/%.yy.c.o)
 obj-fxg1a  := $(call obj,src-fxg1a)
 obj-fxos   := $(call obj,src-fxos) $(call lex,lex-fxos)
 
+# Sed command to copy install path to fxsdk.sh. On Mac OS, BSD sed is used so
+# we need to do it a bit differently with a printf helper to insert a literal
+# newline into the command.
+sed  := '/^PREFIX=\\$$/ a \$(PREFIX)'
+ifeq "$(shell uname)" "Darwin"
+sed  := "$$(printf '/^PREFIX=/ a \\\n$(PREFIX)')"
+endif
+
 # Symbolic targets
 
 all: $(bin)
 
+all-fxsdk: bin/fxsdk.sh
 all-fxg1a: bin/fxg1a
 all-fxos: bin/fxos
 
 # Explicit targets
 
+bin/fxsdk.sh: fxsdk/fxsdk.sh
+	sed -e $(sed) $< > $@
 bin/fxg1a: $(obj-fxg1a) | bin/
 	gcc $^ -o $@ $(lflags)
 bin/fxos: $(obj-fxos) | bin/
@@ -87,24 +99,21 @@ Makefile.cfg:
 
 m644 := -m 644
 m755 := -m 755
-sed  := -i -e '/^PREFIX=\\$$/ a \$(PREFIX)'
 
-# Disable -m on Mac OS and use sed differently
+# Disable -m on Mac OS
 ifeq "$(shell uname)" "Darwin"
 m644 :=
 m755 :=
-sed  := -i '' -e "$$(printf '/^PREFIX=/ a \\\n$(PREFIX)')"
 endif
 
 install: $(bin)
 	install -d $(PREFIX)/bin
 	install -d $(PREFIX)/share/fxsdk
-	install $(bin) $(m755) $(PREFIX)/bin
+	install $(bin:bin/fxsdk.sh=) $(m755) $(PREFIX)/bin
 	install fxos/*.txt $(m644) $(PREFIX)/share/fxsdk
 	install -d $(PREFIX)/share/fxsdk/assets
 	install fxsdk/assets/* $(m644) $(PREFIX)/share/fxsdk/assets
-	install fxsdk/fxsdk.sh $(m755) $(PREFIX)/bin/fxsdk
-	sed $(sed) $(PREFIX)/bin/fxsdk
+	install bin/fxsdk.sh $(m755) $(PREFIX)/bin/fxsdk
 	install fxconv/fxconv-main.py $(m755) $(PREFIX)/bin/fxconv
 	install fxconv/fxconv.py $(m644) $(PREFIX)/bin
 
diff --git a/configure b/configure
index 6984700..ba0fb3f 100755
--- a/configure
+++ b/configure
@@ -92,7 +92,9 @@ esac; done
 
 gen()
 {
-	echo "PREFIX  = $PREFIX"
+	# Allow an install script to change the destination at the last second
+        # to have all files in a separate root before packaging
+	echo "PREFIX  ?= $PREFIX"
 	echo -n "TARGETS ="
 
 	[[ $BUILD_fxsdk  = 1 ]] && echo -n " fxsdk"
diff --git a/fxsdk/fxsdk.sh b/fxsdk/fxsdk.sh
index 9d13357..73e7ea0 100755
--- a/fxsdk/fxsdk.sh
+++ b/fxsdk/fxsdk.sh
@@ -2,7 +2,7 @@
 
 set -e
 
-# Note: this line is edited at install time to insert the install folder
+# Note: this line is edited at compile time to insert the install folder
 PREFIX=\
 
 usage_string=$(cat << EOF
@@ -210,9 +210,9 @@ LDFLAGS_CG += -Wl,-Map=build-cg/map
 
 # Here you can add fxconv options for each converted file, individually.
 # The syntax is "<type>.<file>". For example, to specify the parameters for a
-# font name "hexa.png", you might write:
+# font named "hexa.png", you might write:
 #
-#   FONT.hexa.png = charset:print grid:size:3x5 grid.padding:1
+#   FONT.hexa.png = charset:print grid.size:3x5 grid.padding:1
 EOF
 }